Cryptogram

How to play

Under the passage there is one box for each ciphertext letter. Type the letter you think it stands for and it fills in everywhere at once. Typing moves you on to the next unsolved letter; Backspace clears a box and stays put.

Clicking a letter in the passage jumps to its box. The small number under each box is how often that letter appears, which is free information — it only counts what is already in front of you.

Rules and controls — Zerdly's preset

1. Each letter of the original was replaced by a different letter, consistently throughout.
2. You decide what each ciphertext letter stands for.
3. One ciphertext letter means one plaintext letter, everywhere — which is what makes the puzzle solvable at all.
4. No letter ever stands for itself. The cipher is generated as a derangement, so a letter is never its own answer.
5. You finish when the passage reads correctly. Punctuation and spacing are printed for you and never count against you.

And one house rule, which is Zerdly's choice rather than a rule of the game:

• In most presets the same plaintext letter may sit in two boxes at once. Real solving is full of “it is either this one or that one”, and refusing the thought only makes you hold it in your head.
• Strict Mapping turns that off. A plaintext letter can be spoken for once, so every entry is a commitment. That is the preset with a changed rule rather than a changed size, and it is worth 25 per cent more.

Every passage was written for Zerdly

Cryptograms are traditionally built on quotations. These are not. All 198 passages here were written for this game, which means there is no famous saying to half-remember and nobody who could have been misquoted.

It also means they could be written to be solvable. Each one uses ordinary words, avoids names and numbers entirely, and carries enough short common words to give you a way in — which is a different requirement from being memorable, and not one a quotation is chosen for.

Presets

• Short Phrase — One short line, with the letter counts on show and a hint when you want one. About seventeen of the twenty-six letters actually turn up, so it is the quickest way in.
• Long Passage — A longer line — a bigger puzzle rather than a different one. Nearly the whole alphabet appears, so there is more to place, and more to go on while you place it.
• Strict Mapping — The rule changes: a plaintext letter may be spoken for only once, so you cannot park E on two letters and decide later. Every assignment becomes a commitment. Worth more.
• No-hint Expert — A long passage, strict mapping, no hint button and no letter counts. Everything you need is on the page; none of it is added up for you.
• Practice — Wrong letters are marked as you go, so you can learn what a bad guess looks like before it costs you an hour. Nothing here is scored or recorded.
• Daily Cipher — One cipher a day, the same for everybody, built from the date. Medium length, ordinary rules, letter counts on show.

Tips

• Start with the one-letter words. In English there are only two that matter, so a single letter standing alone is nearly always A or I.
• Then find the three-letter word that appears most. It is very often THE, and it hands you three letters at once — including E, which is the commonest letter in the language.
• Look for doubled letters. A pair inside a word is far more likely to be LL, SS, EE, OO or TT than anything else.
• An apostrophe near the end of a word is a gift: what follows is almost always S, T or RE.
• Use the counts as a starting order rather than as an answer. The commonest letter in a short passage is often E and is quite often not — which is exactly why a short one is solved on word shapes.
• In Strict Mapping, work out what you can afford to claim before you claim it. Clearing a box is free; being wrong about it for ten minutes is not.

Leaving in the middle of a cipher

There is no clock, so nothing is lost by stopping. Your letters, the hints you have spent and the cipher itself are restored exactly as you left them.

Every stored letter is re-checked against the rules as it is restored, rather than trusted. If a saved puzzle no longer makes sense, the game builds a fresh one instead of dropping you into a position you were never in.

Privacy and local play

Everything runs in your browser. Your current puzzle, your settings, your best scores and the passages you have seen recently are kept on this device only, and the button under the game clears them without touching any other Zerdly tool. No account, no sign-in, and nothing about your play leaves the machine you are on.

Questions

Where do the passages come from?

Every one of them was written for Zerdly. There are 198 of them and not a single one is a quotation. That is deliberate: an attributed quote makes a claim about who said it, the internet is full of confident misattributions, and repeating one would mean publishing a small falsehood. Writing the lines ourselves removes the question entirely — and it lets each one be written to be good cryptogram material rather than merely famous.

Can a letter ever stand for itself?

No, never. The cipher is generated as a derangement, which is a shuffle with no letter left where it started. That matters for fairness as much as for difficulty: a cipher that happened to fix three letters would be far easier than one that fixed none, and nothing on screen would explain why.

Do the letter counts under each box count as cheating?

They cost nothing, because they only count what is already printed in front of you. Anybody can count the ciphertext by hand; the display just saves the counting. The hint is the thing that costs, because it tells you something you could not have worked out from the page.

Why can I put the same letter in two boxes?

Because real solving is full of “it is either this one or that one”, and a board that refuses the thought only makes you hold it in your head. It is genuinely optional, so it is a house rule rather than a rule of the game — and Strict Mapping is the preset where you cannot.

What makes Strict Mapping different from just being harder?

It changes what you are allowed to do rather than how much there is to do. A plaintext letter can be spoken for only once, so every entry is a commitment rather than a note. It shares its passage length with the Daily, so the difference between them really is the rule and nothing else.

Is a long passage a different kind of puzzle?

Not really, and it would be easy to claim otherwise. Frequency analysis works about as well on a short passage as on a long one — we measured it. What length actually changes is how much of the alphabet turns up: around seventeen distinct letters in a short line against twenty-one in a long one. So a long passage is a bigger puzzle, not a different one, and it is offered as a difficulty.

How does the hint choose which letter to give?

It fills in the commonest ciphertext letter that you have not already got right, and then locks it so it cannot be changed. It never leaves the board in a contradictory state: if another box was holding that plaintext letter, that box is cleared.

How is a cipher scored?

12 points for each distinct letter in the passage, so a longer one is worth more. Strict Mapping adds 25 per cent. Each hint costs 30, and the total never drops below zero. Practice rounds are never scored at all.

Why does Practice not keep a score?

Because it marks wrong letters while you play, which is most of the way to the answer. A best set that way would not be comparable with one earned without it, so Practice keeps no record — the game refuses to store one rather than relying on anyone to remember not to.

Does punctuation ever count against me?

No. You never type punctuation, so it can never be wrong. The passage is checked on its letters alone, which is why a comma in the wrong place cannot fail a puzzle you have solved.

What happens if I close the tab in the middle?

Nothing is lost. There is no clock, so your letters, your hints and the cipher itself all come back exactly as you left them. Every stored letter is re-checked against the rules as it is restored, so a saved puzzle can never put you in a position you were not actually in.

Is anything sent to a server?

No. The passages, the cipher and your progress all run in your browser. There is no account, and clearing this game's data leaves every other Zerdly tool untouched.

Related interactives

• Word Ladder — turn one word into another, one letter at a time.
• Word Guess — one hidden word, a letter at a time.
• Letter Grid Hunt — trace words through touching letters.
• Word Scramble — the letters loose in front of you.